Fix patchelf RPM builds

http://hydra.nixos.org/build/17037187

pkgs/build-support/release/functions.sh

@@ -2,7 +2,7 @@ findTarball() {
     local suffix i
     if [ -d "$1/tarballs/" ]; then
         for suffix in tar.gz tgz tar.bz2 tbz2 tar.xz tar.lzma; do
-            for i in $1/tarballs/*.$suffix; do echo $i; return; done
+            for i in $1/tarballs/*.$suffix; do echo $i; break; done
         done | sort | head -1
         return
     else